Interchangeable flat-back front tooth.



BAC

L1-PMO amori FILED Nov. x9,

TERCHANGEABLE FLAT K FRONT TOOTH.

Patented June 17, 1913 HARRY Application led November 19, 1912.

Speciication ef Letters Patent.

Pa inne 17, T913.

Serial No. 732,325.

T o all whom z'lf may concern Be it known that I, HARRY C. Dalles. citizen of the United States, residing at York, Pennsylvania, have invented certain new and useful Improvements in lnterchangeable Flat-Back Front Teeth, of which the following is a specification.

The invention relates `to flat back interchangeable front teeth, and the fastening therefor, some of the objects being to enable the dentist to readily adjust the teeth to the requirements of the -lpatients mouth; to provide a constructioii Which will take care of the surplus cement;` also ta construction which will efectually resist strain` in attaching the teeth and strains incident to.

actual use in the mouth, and which will permit rinding without danger of chipping the toot.

The invention consists in the features and combination and arrangement of parts here inafter described and particularly pointed out in the claims.

In the drawin Figure 1 is a rear view of. a tooth accor ing to one form of my invention; Fig. .2 is' a longitudinal scc-tional view; Fig. 3 is a cross sectional View; Fig. 4 is a View of the backing plate in perspective: Fig. 5 is a sectional View of the tooth in place; Fig. 6 is a View of a modified forni of facing. Fig. 7 is e View of a plate with its pin located higher up than in Fig. 4. Fig. S is a View similar to Fig. 6 showing a slightly different relation as to proportion between the bore and the recess.

In these drawings, 1 is the tooth, it heing understood that my.. inlprovementrclates particularly to front interchangeable teeth, This tooth has a dat back adapted to tit. the vertical face of the backing plate shown in Fig. 4. This tooth is molded with a recess 2 in its'lat face intermediate its upper and lower ends, and the tooth is provided with a bore or longitudinal cavity 3 extending from the ridge lap past the intermediate recess to about one-eighth inch vof thecuttng edge of the tooth, this bore or channel terminating at a point below the lower edge of the recess. The recess is wider than the diameter of the bore and preferably deeper, as shown 'in the cross length this latter portion of the pin is such that its end will .find a bearing at the bottom of the bore in the tooth, while ht the same time the shank of the pin or that portion which extends at right angles to the hack plate affords hearing for the tooth, the lower edge of its recess-l engaging this .shank portion and resisting upward strains, either in adjusting the tooth to the plate Gr when. the tooth is in actual use. In other` words, this strain is distributed by the tooth hearingy upon both the end o the pin and upon its shank. Now, when it is desired to adjust the tooth higher np on the hacking to compensate for shrinkage of the gums, the end of the pin can be cut away and. the lower edge of the recess will also be cut away sufficiently to allow the tooth to be pushed higher up on the plate. In this new position, however. the tooth. will hear the in at the two points mentioned, e., on the shank and on the end of the pin te distribute the strain of the upward thrust in biting or in tiring tooth to the plate, The pin lits thev bore 3 with ninety. lt is, however. of a diameter smaller than the Width of the recess, facilitating its ready insertion to aline with the core by a move ment of the tooth in a direction. et right angles te the face of the hacking plate, and he'zause ot the extra width of the recess in respect to the diameter of the pin, provi sion is thus made for taking care of any sern plus cement which is squeezed out from the here which the of vthe pin enters for this surplus can till the recess and can Contact with the backing plnteito cement or lock the tooth thereto. Surplus cement will also be taken care of by the horeifezrtendinv from the recess and opening at the lap race 8, the cement entering or passing along this bore and exuding at the lap face. lt'wili iw. noticed that there is a considerable thickness of porcelain under the end of the I' pin, and also in rear of the pin bridging the to many dentists.

bore, all of which tends to strengthen the tooth at this point. Furthermore, the pin is tapered at its end, the bore being tapered to correspond, and by reason of this there will be more porcelain left between the bore and the labial face oi' the tooth than would be the case were the pin nottapered. This increases the strength of the tooth and en ables the tooth to be ground on its labial face without danger of splitting, and without making the wall. so thin as to make the pin show through. The strength of the -tooth is preserved also by the portion at 6 bridging the bore of the tooth at a point labove the recess.

In practice the recess is first filled with cement, and the tooth or facing is then slipped onto the pin and pushed up, the end of the pin bottoming at the base of the bore or opening, and the edge of the tooth at the lower end of the recess comingNagainst the shank of the pin. A larger amount of cement can be used, the dentist not having to exercise the same care as in practice heretofore because the excess cement will be taken care of as above described. All holes in facings or teeth are to be the same distance from the cutting edge, and all pins are to be the same size and length for all sizes of facings` and 4the adjustment of the facing upwardly toward the gingival arch is to be effected by grinding the end of the pin and Athe lower edge of the recess, this enabling the facing to lbe'pushed up along the face of the hacking while at the same time maintainingv a firm bearing thereon throughout.

the entire flat back face.

ln the form of the invention illustrated in Fig. 6, the facing is shorter than that shown in the other figures. It is used, however.l with the same form of back plate, and substantiallv right angular attaching pin, the main difference being that there is no bridge piece 6 above the recess. but this recess extends clear through to the lap face 3 of the facing. This recess lie's above the shank of the pin when this is in place, affording an escape for the excess cement and permitting the bodv of cement in the recess and bore to unite with the backing plate for aflixing the facing thereto, it not being necessary with my construction to have any cement between .the flat back face of the tooth and the face iof the backing plate. which is objectionable This tooth can be adjusted like the tooth first described. and in all adj' 'laments it provides an escape above the pin and through the lap face for theescape of the cement.

, I eorrugate the pin to present a surface to be engaged by the cement.

'it wili be observed that the bore which refseivea the pin is entirely surrounded with porcelain, thus removing the possibility oi the facing being split under the strain mei dent to the upward pressure. The enlarged recess directs the pin to the bore and the bore centers the facing accurately.

It will be observed that the tooth can be adjusted upwardly and always maintain its firm bearing on the backing plate, and exactly the same relation to the pin so far as the holding function of this pin is concerned. The bore in which the pin accurately fits is not altered by this adjustment, and therefore the accurate fitting of the pin and the .accurate centering of the tooth or facing is not interfered with. The adjustment of the facing takes place in a direction parallel with the bore or drilled opening, and thus it is necessary only to cut off the end of the pin and cut away the edge at the lower end of the recess at the back of the tooth in order to enable this adjustment to be made.

Having thus described my invention what I claim 1S 1. In combination a flat back front tooth` having a longitudinal bore extending from near the cutting edge through to the ridge lap, and substantially parallel with the flat back face, and an enlarged recesslying above the lower end of the bore extendin from the back face and communicating Wit the bore, a backing late and a pin of substantially right angu ar form, the down-turned end of which is substantially parallel with the face of the backing plate, said in restin at its end in the bottom of the ore and caring with its shank on the lower edge of the recess, a ortion of the recess and of the bore lying a ove theshank of the pin when said pin is inserted, substantially as'described.

`2. A flat back front tooth having a bore rrextending parallel with the flat back and lap leaving a portion of the porcelain bridg. ing the bore, the length of said recessv ver-- tically being greater than the distance from the bottom of the bore to the lower edge of the recess, substantially as described.

4. In combination a flat back front tooth having a longitudinal bore with a. recess communicating therewith at an intermediate point of said bore, leaving bri g portions of the porcelain above and low the recess, said bore extending parallel with the bank Het face and opening through the ridge In testimon whereof, I ax my signature hp, und a kmcknghplatehavg a righ;l anin presence o two witnesses.

fnazpin o pass trou x sai mtez'me inte ecess and enter said hte, Said in having HARRY C' DANCE' fsldependng particu aralle'l su stantially Witnesses:

with the front face of t e backing p1ate,sub EDWIgI MOUHTFOBD,

suntaly es described. EDWAJ. LoUoxs. 

